1. Field of the Invention
The present invention relates to a command conversion device connected between an amplifier device and a content reproduction device for allowing the amplifier device and the content reproduction device to be controlled from each other.
2. Description of the Related Art
There are conventional systems in which a plurality of reproduction devices (CD players, MD recorders, etc.) are connected to a plurality of audio input terminals of an amplifier device, wherein the amplifier device and the reproduction devices are controlled from each other by exchanging commands therebetween. In such a system, for example, when the power of the amplifier device is turned ON, the amplifier device sends a reproduction device a command to turn the power ON. In response to the command, the reproduction device turns the power ON. When a reproduction device starts reproducing a content item, the content reproduction device sends the amplifier device a command to “turn ON the power and switch the selector”. In response to the command, the amplifier device turns ON the power thereof and switches the selector to the audio input terminal to which the reproduction device is connected. Thus, as the operator operates one of the amplifier device and the reproduction device, the other device automatically performs an operation corresponding to the operator's operation. This eliminates the need for the operator to operate both the amplifier device and the reproduction device, thus making the operation much easier.
Commands exchanged between the amplifier device and a reproduction device are unique to the type of the device connected to the amplifier device. For example, CD player commands are used for controlling the amplifier device and a CD player from each other. MD recorder commands are used for controlling the amplifier device and an MD recorder from each other. The MD recorder cannot be operated by a CD player command even if it is received from the amplifier device. This prevents an erroneous operation of a reproduction device connected to the amplifier device.
However, a conventional system as described above has the following problem. If the reproduction device connected to the amplifier device is incompatible with commands that can be used with the amplifier device, the reproduction device and the amplifier device cannot be controlled from each other. Then, the operator needs to operate each of the amplifier device and the reproduction device separately, which is quite time-consuming. For example, if a portable reproduction device (e.g., a hard disk player) that is incompatible with commands that can be used with the amplifier device is connected to the amplifier device, the operator needs to press a key on the portable reproduction device to bring it to a play mode, turn ON the power of the amplifier device, and switch the selector of the amplifier device to the audio input terminal to which the hard disk player is connected.